'Stream Daylighting' as an approach for the renaturalization of riverine systems in urban areas: Istanbul-Ayamama Stream case

This paper discusses the interactions between riverine systems and urban areas with a focus on the ecosystem services (ESs) provided by urban rivers and the threats they have been confronting in the urbanization process. Urbanization, as a global demographic trend, led to the increase in migration of people from rural regions to urban areas (especially in developing or under-developed countries) that caused congestion problems in cities with a number of documented effects on urban socio-ecological systems. Due to the urban population increase and expansion of anthropogenic activities, urban riverine systems as one of the most vulnerable components of urban ecology have been exposed to the crisis of ecological deterioration. As a result, their hydro-morphological characteristics changed, crucial functions and aquatic habitats have been lost. From this point of view, Ayamama Stream Watershed is evaluated in the context of the study due to its critical location in Istanbul and a conceptual model framework called 'Co-MISDAL' is developed referring to the 'renaturalization' of buried sections of the river network by using 'Stream Daylighting' method under the key principles of 'Ecohydrology'. Three-stage research methodology is used in the paper and 10 different practices of Stream Daylighting from 4 different regions (USA, Switzerland, Korea, Canada) are comparatively analyzed to develop Co-MISDAL as a guideline for renaturalization of the Ayamama Stream Watershed that is suffering from the extreme flood events and pollution problems. The research mainly aims to evaluate the effectiveness of ecohydrological approach and renaturalization practices for buried and/or damaged urban riverine systems through Stream Daylighting approach.